1 /* 2 * (C) Copyright 2007 3 * Larry Johnson, lrj@acm.org 4 * 5 * based on rtc/m41t11.c which is ... 6 * 7 * (C) Copyright 2002 8 * Andrew May, Viasat Inc, amay@viasat.com 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License as 12 * published by the Free Software Foundation; either version 2 of 13 * the License, or (at your option) any later version. 14 * 15 * This program is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 * GNU General Public License for more details. 19 * 20 * You should have received a copy of the GNU General Public License 21 * along with this program; if not, write to the Free Software 22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 23 * MA 02111-1307 USA 24 */ 25 26 /* 27 * STMicroelectronics M41T60 serial access real-time clock 28 */ 29 30 /* #define DEBUG 1 */ 31 32 #include <common.h> 33 #include <command.h> 34 #include <rtc.h> 35 #include <i2c.h> 36 37 #if defined(CONFIG_RTC_M41T60) && defined(CFG_I2C_RTC_ADDR) && \ 38 defined(CONFIG_CMD_DATE) 39 40 static unsigned bcd2bin(uchar n) 41 { 42 return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F)); 43 } 44 45 static unsigned char bin2bcd(unsigned int n) 46 { 47 return (((n / 10) << 4) | (n % 10)); 48 } 49 50 /* 51 * Convert between century and "century bits" (CB1 and CB0). These routines 52 * assume years are in the range 1900 - 2299. 53 */ 54 55 static unsigned char year2cb(unsigned const year) 56 { 57 if (year < 1900 || year >= 2300) 58 printf("M41T60 RTC: year %d out of range\n", year); 59 60 return (year / 100) & 0x3; 61 } 62 63 static unsigned cb2year(unsigned const cb) 64 { 65 return 1900 + 100 * ((cb + 1) & 0x3); 66 } 67 68 /* 69 * These are simple defines for the chip local to here so they aren't too 70 * verbose. DAY/DATE aren't nice but that is how they are on the data sheet. 71 */ 72 #define RTC_SEC 0x0 73 #define RTC_MIN 0x1 74 #define RTC_HOUR 0x2 75 #define RTC_DAY 0x3 76 #define RTC_DATE 0x4 77 #define RTC_MONTH 0x5 78 #define RTC_YEAR 0x6 79 80 #define RTC_REG_CNT 7 81 82 #define RTC_CTRL 0x7 83 84 #if defined(DEBUG) 85 static void rtc_dump(char const *const label) 86 { 87 uchar data[8]; 88 89 if (i2c_read(CFG_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 90 printf("I2C read failed in rtc_dump()\n"); 91 return; 92 } 93 printf("RTC dump %s: %02X-%02X-%02X-%02X-%02X-%02X-%02X-%02X\n", 94 label, data[0], data[1], data[2], data[3], 95 data[4], data[5], data[6], data[7]); 96 } 97 #else 98 #define rtc_dump(label) 99 #endif 100 101 static uchar *rtc_validate(void) 102 { 103 /* 104 * This routine uses the OUT bit and the validity of the time values to 105 * determine whether there has been an initial power-up since the last 106 * time the routine was run. It assumes that the OUT bit is not being 107 * used for any other purpose. 108 */ 109 static const uchar daysInMonth[0x13] = { 110 0x00, 0x31, 0x29, 0x31, 0x30, 0x31, 0x30, 0x31, 111 0x31, 0x30, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 112 0x31, 0x30, 0x31 113 }; 114 static uchar data[8]; 115 uchar min, date, month, years; 116 117 rtc_dump("begin validate"); 118 if (i2c_read(CFG_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 119 printf("I2C read failed in rtc_validate()\n"); 120 return 0; 121 } 122 /* 123 * If the OUT bit is "1", there has been a loss of power, so stop the 124 * oscillator so it can be "kick-started" as per data sheet. 125 */ 126 if (0x00 != (data[RTC_CTRL] & 0x80)) { 127 printf("M41T60 RTC clock lost power.\n"); 128 data[RTC_SEC] = 0x80; 129 if (i2c_write(CFG_I2C_RTC_ADDR, RTC_SEC, 1, data, 1)) { 130 printf("I2C write failed in rtc_validate()\n"); 131 return 0; 132 } 133 } 134 /* 135 * If the oscillator is stopped or the date is invalid, then reset the 136 * OUT bit to "0", reset the date registers, and start the oscillator. 137 */ 138 min = data[RTC_MIN] & 0x7F; 139 date = data[RTC_DATE]; 140 month = data[RTC_MONTH] & 0x3F; 141 years = data[RTC_YEAR]; 142 if (0x59 < data[RTC_SEC] || 0x09 < (data[RTC_SEC] & 0x0F) || 143 0x59 < min || 0x09 < (min & 0x0F) || 144 0x23 < data[RTC_HOUR] || 0x09 < (data[RTC_HOUR] & 0x0F) || 145 0x07 < data[RTC_DAY] || 0x00 == data[RTC_DAY] || 146 0x12 < month || 147 0x99 < years || 0x09 < (years & 0x0F) || 148 daysInMonth[month] < date || 0x09 < (date & 0x0F) || 0x00 == date || 149 (0x29 == date && 0x02 == month && 150 ((0x00 != (years & 0x03)) || 151 (0x00 == years && 0x00 != (data[RTC_MONTH] & 0xC0))))) { 152 printf("Resetting M41T60 RTC clock.\n"); 153 /* 154 * Set to 00:00:00 1900-01-01 (Monday) 155 */ 156 data[RTC_SEC] = 0x00; 157 data[RTC_MIN] &= 0x80; /* preserve OFIE bit */ 158 data[RTC_HOUR] = 0x00; 159 data[RTC_DAY] = 0x02; 160 data[RTC_DATE] = 0x01; 161 data[RTC_MONTH] = 0xC1; 162 data[RTC_YEAR] = 0x00; 163 data[RTC_CTRL] &= 0x7F; /* reset OUT bit */ 164 165 if (i2c_write(CFG_I2C_RTC_ADDR, 0, 1, data, sizeof(data))) { 166 printf("I2C write failed in rtc_validate()\n"); 167 return 0; 168 } 169 } 170 return data; 171 } 172 173 int rtc_get(struct rtc_time *tmp) 174 { 175 uchar const *const data = rtc_validate(); 176 177 if (!data) 178 return -1; 179 180 tmp->tm_sec = bcd2bin(data[RTC_SEC] & 0x7F); 181 tmp->tm_min = bcd2bin(data[RTC_MIN] & 0x7F); 182 tmp->tm_hour = bcd2bin(data[RTC_HOUR] & 0x3F); 183 tmp->tm_mday = bcd2bin(data[RTC_DATE] & 0x3F); 184 tmp->tm_mon = bcd2bin(data[RTC_MONTH] & 0x1F); 185 tmp->tm_year = cb2year(data[RTC_MONTH] >> 6) + bcd2bin(data[RTC_YEAR]); 186 tmp->tm_wday = bcd2bin(data[RTC_DAY] & 0x07) - 1; 187 tmp->tm_yday = 0; 188 tmp->tm_isdst = 0; 189 190 debug("Get DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 191 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 192 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 193 194 return 0; 195 } 196 197 void rtc_set(struct rtc_time *tmp) 198 { 199 uchar *const data = rtc_validate(); 200 201 if (!data) 202 return; 203 204 debug("Set DATE: %4d-%02d-%02d (wday=%d) TIME: %2d:%02d:%02d\n", 205 tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday, 206 tmp->tm_hour, tmp->tm_min, tmp->tm_sec); 207 208 data[RTC_SEC] = (data[RTC_SEC] & 0x80) | (bin2bcd(tmp->tm_sec) & 0x7F); 209 data[RTC_MIN] = (data[RTC_MIN] & 0X80) | (bin2bcd(tmp->tm_min) & 0X7F); 210 data[RTC_HOUR] = bin2bcd(tmp->tm_hour) & 0x3F; 211 data[RTC_DATE] = bin2bcd(tmp->tm_mday) & 0x3F; 212 data[RTC_MONTH] = bin2bcd(tmp->tm_mon) & 0x1F; 213 data[RTC_YEAR] = bin2bcd(tmp->tm_year % 100); 214 data[RTC_MONTH] |= year2cb(tmp->tm_year) << 6; 215 data[RTC_DAY] = bin2bcd(tmp->tm_wday + 1) & 0x07; 216 if (i2c_write(CFG_I2C_RTC_ADDR, 0, 1, data, RTC_REG_CNT)) { 217 printf("I2C write failed in rtc_set()\n"); 218 return; 219 } 220 } 221 222 void rtc_reset(void) 223 { 224 uchar *const data = rtc_validate(); 225 char const *const s = getenv("rtccal"); 226 227 if (!data) 228 return; 229 230 rtc_dump("begin reset"); 231 /* 232 * If environmental variable "rtccal" is present, it must be a hex value 233 * between 0x00 and 0x3F, inclusive. The five least-significan bits 234 * represent the calibration magnitude, and the sixth bit the sign bit. 235 * If these do not match the contents of the hardware register, that 236 * register is updated. The value 0x00 imples no correction. Consult 237 * the M41T60 documentation for further details. 238 */ 239 if (s) { 240 unsigned long const l = simple_strtoul(s, 0, 16); 241 242 if (l <= 0x3F) { 243 if ((data[RTC_CTRL] & 0x3F) != l) { 244 printf("Setting RTC calibration to 0x%02lX\n", 245 l); 246 data[RTC_CTRL] &= 0xC0; 247 data[RTC_CTRL] |= (uchar) l; 248 } 249 } else 250 printf("environment parameter \"rtccal\" not valid: " 251 "ignoring\n"); 252 } 253 /* 254 * Turn off frequency test. 255 */ 256 data[RTC_CTRL] &= 0xBF; 257 if (i2c_write(CFG_I2C_RTC_ADDR, RTC_CTRL, 1, data + RTC_CTRL, 1)) { 258 printf("I2C write failed in rtc_reset()\n"); 259 return; 260 } 261 rtc_dump("end reset"); 262 } 263 #endif /* CONFIG_RTC_M41T60 && CFG_I2C_RTC_ADDR && CONFIG_CMD_DATE */ 264